1. Field of the Invention
The present invention relates to an image forming apparatus such as a laser printer, a copier, or the like, and more particularly to a developing unit-toner cartridge assembly of an image forming apparatus in which toner feeding and recovering paths are opened and closed according to mounting and removal of a developing unit and a toner cartridge.
2. Description of the Related Art
Generally, an image forming apparatus performs a desired printing process in a computer network. A representative example can be taken from a laser printer, which, unlike dot printers or inkjet printers, uses an electro-photographic printing method. According to the electro-photographic printing method, an electrostatic latent image is formed when a laser beam is projected onto a photosensitive medium that is charged with electricity, and the electrostatic latent image is visualized by toner particles, and transferred and printed on a paper. The laser printer has a printer body housing an engine portion for forming an image, and a paper cassette for feeding the paper to the engine portion.
The engine portion has a developing unit, a Laser-beam Scanning Unit (LSU), and a fixing unit for fixing the toner image on the paper.
The developing unit has a photosensitive drum charged by a proper discharging method, such as a corona discharge. On the photosensitive drum, the electrostatic latent image is formed by the laser beam projected from the LSU. Further, the developing unit has a charging means for charging the photosensitive drum, a developing means such as a developing roller for conveying the toner from the developing unit to the photosensitive drum, and a cleaning means for cleaning waste toner remaining on the photosensitive drum.
The developing unit is connected, respectively, to a toner cartridge for feeding the toner into the developing unit, and a waste toner recovering device for collecting the waste toner after the printing process.
When the toner cartridge is connected to the developing unit, the toner cartridge is interconnected with the developing unit through a toner feeding path. Accordingly, the toner is fed from the toner cartridge to the developing unit. After being fed, the toner is attached onto the electrostatic latent image area formed on the photosensitive drum, and then transferred to the printing paper passing through the photosensitive drum. During this process, a small amount of toner is not transferred to the printing paper, but remains on the photosensitive drum. The remainder of the toner is removed by the cleaning means of the developing unit, and is recovered in a waste toner recovering device connected to the developing unit through a waste toner recovering path.
The toner feeding path from the toner cartridge to the developing unit, and the waste toner recovering path from the developing unit to the waste toner recovering device, are opened and closed by opening/closing members respectively mounted thereon.
More specifically, in the conventional combination of the developing unit and the waste toner recovering device, when the developing unit is separate from the waste toner recovering device, the waste toner recovering path is closed as a discharge port shutter closes a discharge port of the developing unit, while a receiving port shutter closes a receiving port of the toner recovering device. When the developing unit is connected to the waste toner recovering device, the discharge port shutter is aligned with the receiving port shutter. In such a situation, as a user manually rotates the receiving port shutter in a predetermined direction, the discharge port shutter is rotated by the rotation of the receiving port shutter, and accordingly, the waste toner recovering path is closed.
Further, in the event that the developing unit is improperly connected to the waste toner recovering device, the receiving port may remain in a closed state while the discharge port is opened by the rotation of the discharge port shutter. If the printing process is performed in such a state, the waste toner is not discharged properly, and accordingly, printing quality may deteriorate. Further, due to the presence of the waste toner, internal components of the printer can be contaminated.
The present invention has been made to overcome the above-mentioned problems of the related art, and accordingly, it is an object of the present invention to provide a developing unit-toner cartridge assembly of an image forming apparatus in which a toner feeding path and a toner recovering path are opened and closed by connection/separation of the developing unit and the toner cartridge.
The above object is accomplished by a developing unit-toner cartridge assembly for an image forming apparatus in accordance with the present invention, including: a developing unit mounted on an engine portion of a body of the image forming apparatus, the developing unit comprising an opening/closing member for opening and closing a toner inlet formed in an outer casing of the developing unit; and a toner cartridge removably mounted in the developing unit, the toner cartridge comprising first opening/closing means for opening and closing a toner feeding port formed in an outer casing of the toner cartridge, and second opening/closing means for restricting, and thereby opening and closing, the opening/closing member while the toner cartridge is mounted and removed to/from the developing unit.
The first opening/closing means includes: a toner feeding roller pivotally disposed within the toner cartridge, the toner feeding roller having a slit formed therein corresponding to the toner feeding port; and a pivotal handle formed on a leading end of a pivotal shaft of the toner feeding roller. The opening/closing member includes: an inlet cover slidably mounted on the outer casing of the developing casing for opening/closing the toner inlet; and a portion defining a locking hole on an upper surface of the inlet cover, through which hole the second opening/closing means is inserted for closing the inlet cover during removal of the developing unit from the toner cartridge. The second opening/closing means includes: a supporting projection protruding from the outer casing of the toner cartridge for supporting an end of the inlet cover by contact; and a stopper elastically disposed on the outer casing of the toner cartridge at a predetermined distance from the supporting projection, the stopper being inserted into or withdrawn from the locking hole.
The developing unit further includes an outlet cover for opening and closing a toner outlet formed in the outer casing of the developing unit, and the toner cartridge further comprises a recovery cover for opening/closing a toner recovery port formed in the outer casing of the toner cartridge so that, during the mounting and the removal of the toner cartridge with respect to the developing unit, the outlet cover and the recovery cover are restricted and, accordingly, opened and closed, respectively, by third opening/closing means formed on the toner cartridge and fourth opening/closing means formed on the developing unit, respectively.
The outlet cover is slidably connected to the outer casing of the developing unit for opening and closing the toner outlet, and has a first locking rise and a second locking rise protruding in a parallel manner from an upper surface of the outlet cover at a predetermined distance therebetween for contact with the third opening/closing means.
The third opening/closing means includes: a first hook elastically pivotable on the outer casing of the toner cartridge for restricting or releasing an inner side of the recovery port cover when the recovery port cover opens and closes the toner recovery port; a second hook opposed to the first hook on the cartridge casing for being pivoted in a relative movement with the first hook; and a third locking rise and a fourth locking rise formed on the cartridge case in a diagonally opposed manner with respect to each other across the recovery port cover. During the mounting and the removal of the toner cartridge with respect to the developing unit, the first and second hooks are pivoted by contact with the first and the second locking rises protruding from the outlet cover.
The fourth opening/closing means includes: a third hook elastically pivotable on the outer casing of the developing unit for restricting movement of the outlet cover by contacting with the locking projection; and a fourth hook elastically pivotable on the outer casing of the developing unit in such a manner as to be opposed to the third hook across the outlet cover, the first hook restricting the movement of the outlet cover by contacting with the locking hole formed on a side of the outlet cover, and the third and fourth hooks being pivoted by contact with the third and the fourth locking rises when the toner cartridge is mounted and removed with respect to the developing unit.
As described above, according to the present invention constructed as above, since the toner feeding path and the toner recovering path are opened and closed by relative operation of the developing unit and the toner cartridge during mounting and removal of the toner cartridge with respect to the developing unit, the user does not have to perform separate jobs in order to open and close the toner feeding path and the toner recovering path.